Holding tank

Discussion of AC's, plumbing and sanitation related issues.
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John Easley
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Re: Holding tank

Post by John Easley »

Roxanne, the situation you describe sounds similar to what we experienced. You could see matter intermittently flowing through the suction hose but it wasn't a steady flow. Boats in the south are particular prone to small critters like mud daubers making a nest in the vent and restricting the flow. A local marine mechanic can probably show you where that vent hose is. Remove it and blow it out with air. If it's already clear, then what Viper described is something you should investigate... and that turned out to be our problem. We have an electric overboard waste pump system connected to our holding tank and that system has a vent, too. That vent was allowing in more air than the suction system was expecting. We fixed it by installing a valve inline before the overboard discharge pump and closing the valve. Now the suction pump makes quick work of it.
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Re: Holding tank

Post by Solana »

Good info - ours usually emits that horrible smell with the first flush after we've been gone for the week. Maybe were aren't letting enough water flush out before we leave.
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Wsullivan71
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Re: Holding tank

Post by Wsullivan71 »

Another trick we learned from RVing is to dump a load of ice into the toilet and flush it into the holding tank. Take the boat out for a ride and the ice will break up any solids and eventually melt. Then pump it out as normal.
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Re: Holding tank

Post by Midnightsun »

Wsullivan71 wrote:Qr Bbpost Another trick we learned from RVing is to dump a load of ice into the toilet and flush it into the holding tank. Take the boat out for a ride and the ice will break up any solids and eventually melt. Then pump it out as normal.


Somebody needs to explain this to me as this "trick" is not new and have heard about it dozens of times, problem is there is no way in hell this will do anything at all IMHO. If you dump ice into the holding tank in the summer which we will say is 75-80 F and by the time you untie and motor out of the marina to start trying to slosh this around I would have to assume there is no ice left! If someone has a secret on keeping ice cubes from melting in warm sewage please tell me as I really do not understand. :captain:
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Re: Holding tank

Post by Viper »

Was easier to do years ago when most tanks had clean-out ports. We'd pump out then fill the tank to 2/3 with water and head out. Once in an area we can throttle up, we'd remove the access cover and pour in a few bags of ice. Once there's a few bags in there, the water is cold enough to to keep the ice from melting too fast. Take the boat for a spin and go over your own wake several times and you're done. Head back in and wait a couple of hours just to ensure all the ice is melted then pump out. Did a great job.

If there is no access, it's difficult to get that much ice in there. And you can't flush ice down the toilet either in an electric or Vacuflush or you're going to break something, I wouldn't recommend it. Vacuflush systems have a sensor pack on top of the tank that can be removed and would provide a means to dump a lot of ice in there but you run the risk of damaging the sensor array with all that ice banging up against it.

The best thing to do to keep the tank relatively clean is pump out often and use a product that will break down the solids. Some products use a lot of chemicals to accomplish this while others use a more natural approach with digestive enzymes. I've gone the enzyme route for a few years now and am happy with the results. There's a few brands producing these types of products now.
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Re: Holding tank

Post by Viper »

I should add that some marinas are pulling the chemical based treatments off their shelves. The reasons are two fold; the chemicals can't be good for the environment and eventually end up in our ground water, they're also not very good for the septic systems most marinas are on. Apparently enzyme based products have very little impact on the environment and promote septic system health which is beneficial for the marina, so it's smart for them to manage what goes into their septic systems.
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